The present invention relates to a method for making a curable coating composition particularly useful as a top coat in multi-layered coating systems. Base coat-clear coat systems have found wide acceptance in the past decade as automotive finishes. Continuing effort has been directed to such coating systems to improve the overall appearance, the clarity of the top coat, and the resistance to deterioration. Further effort has been directed to the development of coating compositions having low volatile organic content (VOC).
Previous efforts at improving the etch resistance and durability of coatings suggested the use of anhydride resins having pendant non-cyclic anhydride moieties in combination with resins that react with the polyanhydride resins to cure under curing conditions. However, a continuing need exists for coating formulations which can be sprayed at exceptionally low VOC and which exhibit outstanding performance characteristics after application, and particularly resistance to environmental etching.